1. Field of the Invention
The present invention relates to a vehicle body reinforcement structure desirable for improving the rigidity at a connecting portion between closed section structures without welded joints.
2. Description of the Related Art
Since a connecting portion on a vehicle body such as a connecting portion between a roof side portion and a center pillar largely contributes to improving the vehicle body rigidity, the rigidity at the connecting portion is improved by reinforcing the connecting portion.
An example of the reinforcement of a connecting portion on the vehicle body as described above will be explained with reference to FIGS. 11A and 11B.
FIGS. 11A and 11B are perspective views showing how a conventional reinforcement of a connecting portion on the vehicle body is carried out.
FIG. 11A shows a state in which a pillar side reinforcement plate 104 is placed on a roof side reinforcement plate 103 in such a manner as to form a T-shape and is welded thereon for fixation in the interior of a connecting portion 102 between a roof side portion 100, which is a closed section structure, and a center pillar 101, which is also a closed section structure.
FIG. 11B is a sectional view taken along the line XIxe2x80x94XI in FIG. 11A, in which reference numeral 105 denotes an outer panel; 106: an inner panel; 107: a roof side rail; and 108: a roof panel.
In the related art described above, the rigidity at the connecting portion 102 between the roof side portion 100 and the center pillar 101 is improved by assembling and welding the roof side reinforcement plate 103 and the pillar side reinforcement plate 104 together in a T-shaped fashion. In this case, three members such as the inner panel 106, the roof side reinforcement panel 103 and the roof side rail 107 have to be assembled and welded together, and four members such as the roof side rail 107, the roof side reinforcement plate 103, the outer panel 105 and the roof panel 108 have to be assembled and welded together. This makes welding difficult, and reduces the working efficiency and deteriorates the productivity.
In addition, for example, in the event that an external force F is applied to the center pillar 101 from the side, a torsion moment M designated by an arrow acts on the roof side portion 100 with the center pillar 101 acting as an arm.
Although the twisting of the roof side portion 100 is reduced by causing the roof side portion 100 itself and the roof side reinforcement plate 103 to bear the torsion moment M, in order to further improve the vehicle crash safety, steering stability and quietness, it is desired that the torsional rigidity at the roof side portion 100 which constitutes the connecting portion 102 be improved further so as to improve in turn the body rigidity as high as possible.
Additionally, for example, the description in JP-A-1053156 entitled xe2x80x9cInterruption, Reinforcement Structure of Hollow Structures, and Interruption, Reinforcement Methodxe2x80x9d is known as the reinforcement structure for closed section structures as shown in FIGS. 12A and 12B.
In FIGS. 12A and 12B, a pillar 201 is described in which a synthetic resin reinforcement member 210 including a plurality of reinforcement plates 211 which are connected to each other by connecting pieces 212, 213 is inserted in a hollow chamber 206 formed between an inner panel 202 and an outer panel 204, and a foamable base material 221 is inserted between the reinforcement plates 211, 211.
In a case where the technique described in this publication is applied to a connecting portion between closed section structures, or, in a case where the technique is used to connect the reinforcement members 210, since the reinforcement member 210 itself is constituted by the plurality of reinforcement plates 211 and the connecting pieces 212, 213, the configuration thereof is very complicated, and therefore it is difficult to form a connecting portion on this reinforcement member 210.
To cope with this, an object of the invention is to provide a vehicle body reinforcement structure which can improve the working efficiency by eliminating welded portions, facilitate the formation of a joint portion and improve the rigidity at a connecting portion where closed section, structures are connected to each other.
With a view to attaining the object, according to a first aspect of the invention, there is provided a vehicle body reinforcement structure for reinforcing a connecting portion where closed section structures such aspillars, roof side portions or the like are connected to each other, the reinforcement structure comprising a first reinforcement material of hard resin disposed in one of the closed section structures, a second reinforcement material of hard resin disposed in the other closed section structure, and a joint portion formed on the first and second reinforcement materials for direct jointing the first and second reinforcement materials.
Welded portions used where reinforcement is effected using sheet steel are eliminated by jointing the first hard resin reinforcement material and the second hard resin reinforcement material which is the same as the first one together at the joint portions. This can improve the working efficiency in reinforcing the connecting portion where the closed section structures are connected together.
In addition, since the first reinforcement material of hard resin is disposed in one of the closed section structures, the second reinforcement material of hard resin is disposed in the other closed section structure, and the joint portion is formed on the first and second reinforcement materials for direct jointing the first and second reinforcement materials, the connecting portion of the closed section structures and the closed section structures themselves become solid, thus increasing the torsional rigidity.
Consequently, the vehicle body rigidity can effectively be improved by improving the rigidity of the connecting portion of the closed section structures which best contributes to the improvement of the vehicle body rigidity.
According to a second aspect of the invention, the joint portion comprises a raised portion formed on the first reinforcement material and a recessed portion formed in the second reinforcement material.
The construction of the joint portion is made simple by constituting the joint portion by the raised portion on the first reinforcement material and the recessed portion in the second reinforcement material. This facilitates the production of the first and second reinforcement materials and hence reduces the production cost thereof.
According to a third aspect of the invention, the joint portion each comprises a plurality of ribs with a foamable resin inserted between the ribs which are adjacent to each other.
The resin inserted in the joint portions expands to fill the space within the connecting portion of the closed section structures. This allows the first and second reinforcement materials to be jointed together strongly to thereby improve the rigidity thereat, the rigidity of the vehicle body being thus improved.